This invention relates generally to imaging methods and apparatus, and more particularly, to methods and apparatus that provide for reduction or elimination of keystone effect.
During an x-ray tomosynthesis exam, the relationship of the x-ray tube to the detector can vary causing tube angulation as described in U.S. Pat. Nos. 5,734,694 and 5,572,567. This tube angulation causes a keystone effect for the projected x-ray field. Typically, mathematical corrections are performed to compensate for the keystone effect. The x-ray field also exhibits a keystone effect whenever the collimator and tube is not perpendicular to the detector.
It would be desirable to, instead of using mathematical corrections to attempt to compensate for the keystone effect, but rather, to eliminate or reduce the keystone effect in the first place.